1. Field of the Invention
Example embodiments of the invention relate to donor substrates, methods of manufacturing organic light emitting display (OLED) devices using donor substrates. More particularly, example embodiments of the invention relate to donor substrates having tightening members relative to display substrates, and method of manufacturing organic light emitting display devices using the donor substrates having the tightening members.
2. Description of the Related Art
An organic light emitting display (OLED) device usually includes various organic layers such as an organic light emitting layer, a hole injection layer, an electron transfer layer, etc. Recently, a laser induced thermal imaging (LITI) process has been developed to form the organic layers of the organic light emitting display device.
In the conventional laser induced thermal imaging process, a donor substrate including organic materials transferred onto a display substrate is placed on the display substrate in an atmosphere, and then the donor substrate is irradiated with a laser to transfer the organic materials onto the display substrate, thereby forming organic layers on the display substrate. However, an air or a gas may be trapped between the donor substrate and the display substrate having a pixel defining layer, while the laser is applied onto the donor substrate after the donor substrate is attached to the display substrate having the pixel defining layer. The trapped air or gas may oxidize and/or may contaminate the organic layers on the display substrate, and thus the organic light emitting display device may easily deteriorates and may have a lower quality of image.
Considering the above-mentioned problems, Korean Patent Application Publication No. 2005-0068777 (entitled “laser induced thermal imaging method for manufacturing an organic light emitting display device”) discloses that a donor substrate is laminated with a display substrate by interposing an adhesive means such as tape or an adhesive film between the donor substrate and the display substrate, and then a laser induced thermal imaging process is performed on the donor substrate. However, in this method of laminating the donor substrate with the display substrate using the adhesive means, small particles and bubbles remaining on a surface of the adhesive means composed of polymer may not completely removed, and may be outgaseed from an organic layer formed on the display substrate after cleaning the display substrate. Accordingly, defects caused by the particles and the bubbles may be generated between the adhesive means and the display substrate and/or the donor substrate. An air may be easily introduced between the display substrate and the donor substrate when such defects occur, and thus a vacuum state between the display substrate and the donor substrate may not be maintained. This may result in damage or deterioration of the organic layers formed on the display substrate.
Meanwhile, an adhesion state between the donor substrate and the display substrate may be reduced because the adhesive means has a relatively larger thickness, so that the organic transfer layer of the donor substrate may not properly transferred onto the display substrate. Additionally, the donor substrate or the display substrate may be distorted or transformed at high temperature while the donor substrate is attached to the display substrate by a thermal pressing process using the adhesive means. Furthermore, severe defects such as particles, remaining adhesive components or static electricity may be generated on the display substrate after a peeling process for detaching the donor substrate from the display substrate. Therefore, failures caused by the defects in manufacturing processes and also an organic light emitting display device may have poor performances.